As for the viscosity, the glutinous part is found in every plant in some degree, as well as in every animal. It preserves the parts from moisture; but will be consumed by heat or time; and it will be a preservative to the plant, till it is destroyed; which was the reason, as I suppose, that Mr. Ray mentions Cassia to have kept good thirty years, the viscosity not having been destroyed by drying.
I suppose the reason, which the Dutch have to dry it, is to make it sooner fit for the market, and possibly fitter for distillation.
You will see from Mr. Combes’s letters and specimens, that he thinks there may be two sorts of Cassia or Cinnamon in Sumatra: possibly there may be the same difference in Ceylon; but, if so, I suspect them both to be only seminal varieties, and that their virtues are the same.
Mr. Barlow, some time since a Surgeon in the service of the India company, made a considerable quantity of oil of the Cassia of Sumatra, which was very little, if any thing, inferior to that drawn from Cinnamon; and it was sold to great profit.
If these plants are really the same, or if they are of equal goodness, supposing there was a small difference in the form of the leaf, it might be well worth the attention of the East India company to try to cultivate these plants in the manner they do in Ceylon; that is, to make plantations in a proper soil; and to have regard to the proper distance from the sea of the place, where they try the experiment: for some plants require to be near the sea, and others far from it, in Sumatra; which is the case of the Mango, and Mangosteen; the one of which must be near the sea, the other at a distance from it.
I think the plants should be suffered to grow strong, to be six or seven years old, and then cut every three years, the bark peel’d off and dried in hot sand, and packed close and kept dry. This I take to be all necessary to be done, to try, if our Cinnamon will not produce as good a price as that of the Dutch.
Perhaps the plants need not stand so long before cut; for the vegetation of plants in hot countries is very great.
There are many other most valuable vegetables in Sumatra, which might be made staple commodities, as sagoe, camphire, several sorts of ginger, rice, and many other, which are foreign to the present inquiry.
But it may not be amiss to recommend it to the traders to Sumatra to bring some quantity of the twig-bark of the true Cassia, well cured; and also to the company, to have a chemist at Sumatra, to extract carefully the oil of Cassia; which is best, and in greatest quantities, produced from the bark of the body, and of the larger branches of the tree: and also that the company would procure an exemption of all customs or duties on Cassia, or on the oil of Cassia, for some time: and also that the college of physicians in their dispensatory would direct Cassia or Cinnamon of Malabar or Sumatra to be used, instead of the Cinnamon of Ceylon; and that the same should be used by apothecaries and distillers, and in all simple and compound waters, in which Cinnamon is used.
Extract of a Letter from Mr. Thomas Combes, dated Fort Marlborough, 5 Jan. 1755.